One person died Saturday when someone drove a car through a crowd of protesters at a white supremacist rally in the city of Charlottesville, Virginia, and two others died later in a helicopter crash that police say was linked to the rally.

At least two dozen other people were injured in the car incident.

Virginia police said they have the driver of the car in custody, and they say they are treating the incident as a criminal homicide investigation.

Late Saturday night, the FBI and the U.S. Attorney's Office announced that they have opened a civili rights investigation into the car incident.

Charlottesville Mayor Mike Singer said on Twitter he is "heartbroken" about the death and urged all those still at the protest site to go home.

President Donald Trump, speaking midafternoon from New Jersey, condemned "the egregious display of hatred, bigotry and violence on many sides" in Charlottesville.

Charlottesville, Virginia

Trump, who was preparing to sign a bill to extend a veterans health care program, called for a "swift restoration of law and order" in the city, adding "no citizen should ever fear for their safety and security."

The helicopter crash Saturday afternoon happened outside the city. The pilot and a passenger were killed. Police have not released details of the crash.

The car ramming occurred as people were leaving the area after police deemed the demonstration unlawful when multiple bouts of violence broke out at the rally between demonstrators and counter-protesters.

Video of the fights show armor-clad, shield-carrying demonstrators trading punches with similarly armed counter-protesters as they marched in the city of Charlottesville.

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Virginia Governor Terry McAuliffe said on Twitter he declared a state of emergency "to aid state response to violence at alt-right rally in Charlottesville."

"The acts and rhetoric in Charlottesville over past 24 hours are unacceptable and must stop. A right to speech is not a right to violence," he wrote in a post on Twitter.

Earlier Saturday, Trump responded to the violence on Twitter, urging all sides to "come together as one" and condemning "hate."

White supremacists carry torches on the grounds of the University of Virginia, on the eve of the "Unite the Right" rally in Charlottesville, Va., Aug. 11, 2017.

The gathering at the University in Virginia, dubbed the “Unite the Right” rally, previously prompted the state’s governor to warn people to stay away from the campus.

A smaller group of demonstrators also rallied Friday night, marching through the campus carrying tiki torches and shouting slogans like “white lives matter,” in preparation for the larger Saturday event.

As they marched Friday the group of white marchers encountered a group of counter-protesters and a small scuffle ensued. A chemical irritant was sprayed into the crowd and police were able to break up the clash. At least one person was arrested and a few people were treated for minor injuries.

The larger rally Saturday was expected to draw crowds of 2,000 to 6,000 people who are upset about the planned removal of a statue commemorating the memory of Confederate Civil War General Robert E. Lee.